APC SILICON 40Kw UPS communication fault

[muds_apc]

hi all,,

I am facing problem in my APC 40kw 400v ups,, alarm shows 'communication to controller lost'

when i gave power to UPS its shows '         system type - N   ''

                                                           V kva - NV

in alaram history its shows communication to controler lost,,

further more describing UPS history,, i turn on UPS after a year,, most probably batteries should be changed,, other then that what could be problem.,,

 thanks in adavance